Recurrent pulmonary symptoms in immunocompromised (IC) patients are a common problem, and they pose diagnostic and therapeutic challenges. Repeat FOB is often performed as it is relatively safe, and more invasive procedures may be contraindicated. The purpose of this study has been to evaluate the diagnostic and therapeutic efficacies of repeat FOB in IC patients. A retrospective chart review was performed for all IC patients undergoing repeat FOB in our Department from 1/1/87 through 6/30/92. Patients were classified as having either "persistent" pulmonary disease (as documented by repeat FOB performed within 30 days of initial FOB), or "new" disease (as documented by repeat FOB performed after 30 days from the initial FOB). In patients with HIV infection, a new diagnosis was found in 8/25 (32%) repeat FOB with new disease and 2/20 (10%) with persistent disease (p=NS). A change in therapy was initiated in 14125 (56%) repeat FOB with new disease, and 7/20 (35%) with persistent disease (p=NS). In hematologic/oncologic disorders, a new diagnosis was found in 10/20 (50%) repeat FOB with new disease, an in 12/42 (29%) with persistent disease (p=O.lO); a change in therapy was initiated in 14/20 (70%) repeat FOB with new disease, and in 24/42 (57%) with persistent disease (p=.NS). In patients with other immunocompromised conditions, a new diagnosis was found in 3/10 (30%) repeat FOB with new disease, and 1/4 (25%) with persistent disease (p=NS); a change in therapy was initiated in 5/10 (50%) repeat FOB with new disease, and in 2/4 (50%) with persistent disease. We have concluded that the diagnostic yield for repeat FOB in patients with HIV infection is equally effective in the presence of new or persistent disease; in patients with hematologic/oncologic disorders and new disease, repeat FOB may be more likely to establish a new diagnosis (p=0.10). A manuscript with these data is nearly completed and will be submitted to the American Journal of Respiratory and Critical Care Medicine. These data extend observations on the diagnostic utility of bronchoscopy, a subject of CCMD research for the past decade.